NATURALLY-OCCURRING ANALOGS OF LYMANTRIA-TESTIS ECDYSIOTROPIN, A GONADOTROPIN ISOLATED FROM BRAINS OF LYMANTRIA-DISPAR PUPAE

Lymantria testis ecdysiotropin (LTE) was isolated from the most promin ent peptide peak corresponding to an active fraction obtained by high pressure liquid chromatographic (HPLC) separation of a homogenate of 1 3,000 Lymantria dispar pupal brains. In this work we examined the othe r active fractions from this separation as well as a second HPLC separ ation of an additional 2,300 pupal brains. Bioassay of the ecdysteroid ogenic effects of each peak on L. dispar testes allowed detection of 2 0 peptide peaks with testis ecdysiotropic activity in addition to LTE. Of these, ten peptides were purified and sequenced. All of them were comparable to LTE in molecular weight. The amino acid sequences of fiv e of the peptides were similar enough to LTE to be considered to be me mbers of an LTE family. However, the other five peptides had no signif icant homology with LTE or with each other. A BLAST database search in dicated LTE family homology with portions of inhibitory peptides such as those inhibiting cytolysis. In contrast, non-LTE ecdysiotropic pept ides, in which undetermined residues designated X were assumed to be c ysteine, were strikingly homologous to portions of vertebrate and inve rtebrate zinc finger peptides and to vertebrate and invertebrate virus proteins. (C) 1997 Wiley-Liss, Inc.(+)